What are common issues when accessing a Gmail mailbox using PHP, especially when hosted on different servers?

One common issue when accessing a Gmail mailbox using PHP, especially when hosted on different servers, is the need to enable less secure apps access in the Gmail account settings. This is because Gmail considers PHP scripts accessing the mailbox as less secure. To solve this, you can enable less secure apps access in your Gmail account settings.

// Enable less secure apps access in Gmail account settings
// Go to your Gmail account settings -> Security -> Less secure app access -> Turn on

// Your PHP script to access Gmail mailbox
// Make sure to use secure methods like OAuth for production environments